Device for adjusting the height of a vehicle

ABSTRACT

The present invention is a system for adjusting the height of vehicles. The vehicle is supported by a hollow cylinder and a piston having an undersized piston skirt is mounted on the suspension system&#39;s coil spring, and sealingly slidable within the cylinder bore. When a fluid is introduced into the expandable pressure space between the piston and the cylinder top, the piston and cylinder are forced apart, raising the vehicle. The undersized piston skirt can extend beyond the end of the cylinder, allowing the piston a greater travel length within the cylinder bore. The invention may be operated manually by a vehicle driver through push buttons, which can be the vehicle&#39;s existing cruise control buttons. Alternatively, the system can be automated using a control unit to automatically adjust ground clearance to avoid collision with obstacles in the vehicle&#39;s path. In another embodiment, the lift system, or any lift system, is prevented from activating, and deactivates (if previously activated) if the vehicle is travelling at excessive speed.

This application is a continuation of, and claims the priority of, U.S.non provisional patent application Ser. No. 14/636,065, filed on Mar. 2,2015, which is a continuation in part of U.S. nonprovisional patentapplication Ser. No. 14/144,002, filed on Dec. 30, 2013, now U.S. Pat.No. 8,967,630 B2, which claimed the priority of U.S. nonprovisionalpatent application Ser. No. 13/595,972 filed on Aug. 27, 2012, now U.S.Pat. No. 8,616,563 B2, which claimed the priority of U.S. provisionalpatent application No. 61/575,718 filed on Aug. 25, 2011, all of whichare hereby incorporated herein by reference.

FIELD OF THE INVENTION

This invention generally relates to lift systems, and more specifically,lift systems for adjusting the ground clearance of vehicles to avoidcollisions with obstacles, such as speed bumps or sloping driveways,which can scrape and damage the underbody of a vehicle.

BACKGROUND OF THE INVENTION

Ground clearance is the distance between any part of a vehicle (otherthan those parts designed to contact the ground, such as tires, tracks,skis, etc.) and the surface upon which the vehicle travels. Vehiclesuspension systems maintain the distance between the axles of avehicle's wheels and the other parts of the vehicle, and are usuallydesigned to maintain a sufficiently high ground clearance to avoidobstacles anticipated to be in the vehicle's path, including (forexample) to avoid scraping when going over a speed bump. Some vehicles,such as off-road vehicles, are designed with a high ground clearance toavoid obstacles encountered in rugged terrain, while other vehicles aredesigned with low ground clearance for high speed performance and/orsportier appearance. However, if the surface over which a vehicletravels has a speed bump, slope or other obstacle, then even if thedistance between the vehicle's axles and other parts of the vehicle ismaintained by the suspension system, the ground clearance at the ends orother parts of the vehicle may not be maintained, so that those ends orother parts may scrape that surface. A suspension system can usemechanical, pneumatic, hydraulic, magnetic, electronic,electro-magnetic, electro-mechanical or other means to support theweight of a vehicle and maintain the distance between the vehicle'saxles and other parts of the vehicle. Conventionally, a suspensionsystem is mechanical, and contains springs to provide a restoring force,and shock absorbers to provide a damping force, to restore the distancebetween the vehicle's axles and other parts of the vehicle after thevehicle encounters a bump or other obstacle. By contrast, a lift systemis a system that increases the ground clearance when activated, anddecreases the ground clearance when deactivated. A lift system can beused together with an active suspension system, that is, a suspensionsystem that actively restores the distance between the vehicle's axlesand the other parts of the vehicle when the vehicle encounters anobstacle, such as a bump. An active suspension system can be, forexample, a system that senses an obstacle or change in the distancebetween the vehicle's axles and other parts of the vehicle, calculatesan appropriate mechanical, hydraulic, pneumatic, magnetic or otherrestoring force or damping force or other force (in response to thesensed obstacle or sensed change in distance between the axles and otherparts), and then applies that calculated force to the suspension systemwhen the vehicle encounters the sensed obstacle or sensed change inground clearance, to restore the distance between the axles and otherparts. By contrast, passive suspension systems, such as conventionalspring and shock absorber systems, do not sense obstacles or changes indistance between the axles and other parts, calculate forces in responseto the sensed obstacle or sensed change in distance between axles andother parts, and then apply the calculated forces to the suspensionsystem.

The benefits of low ground clearance and lower vehicle height arenumerous and include less wind resistance, better fuel economy, betteracceleration, better cornering, and better braking. Another significantadvantage of low ground clearance is that it allows for betteraesthetics such as providing a lower, sleeker, and sportier appearancethat is desired by many drivers.

Many modern vehicles are designed and built with low ground clearancefor the sportier appearance. Vehicle owners also lower their vehicles,through after-market modification, for enhanced performance, fueleconomy and sportier appearance. One of the most common ways to lower avehicle is through the use of a coilover, a vehicle suspension devicethat incorporates a coil spring positioned over and around a shockabsorber shaft that is connected to a shock absorber body. Use of acoilover allows for a limited amount of height adjustment by adjustingthe height of the coil spring's lower mounting point.

Other common ways to lower a vehicle include using shorter coil springson the vehicle's suspension or adjusting the height or length of thesuspension springs.

Reducing a vehicle's ground clearance height frequently results inundesired contact (collisions or scraping) between the vehicle andobstacles in the vehicle's path, such as speed bumps, sloping drivewaysand uneven surfaces. Unfortunately, when contact occurs, the vehicle isoften damaged from the contact. Sometimes the obstacles are too large ortoo tall for the vehicle to travel over them. In the past, other vehiclelift systems have been developed, but they fall short of providing anadequate solution for many reasons. For example, some lift systems aredesigned and built to be vehicle-specific and are not readily adaptableto other vehicles. On the other hand, lift systems designed to fit avariety of vehicles often require the removal or replacement of existingcomponents, resulting in added costs for the replacement components andloss of performance from the removal of critical or beneficial existingcomponents. Such removed components may include coil springs, dustsleeves and bump stops.

Some prior art lift systems employ pressurized rubber air bags or airsleeves to replace coil springs in a suspension system. These systems donot retain the performance characteristics and benefits of metal coilsprings, and incur the added cost of replacing the existing shockabsorbers and/or metal coil springs with air bags or air sleeves.Moreover, components in lift systems that use metal coil springs may beso tall or thick that they do not fit into vehicles with the existingsuspension springs. In such cases, the coil springs must be replacedwith shorter springs resulting in a loss of suspension performance fromthe shorter spring.

Some prior art lift systems use hollow double-walled cylinder designshaving concentric inner and outer cylinder walls. This design iscomplicated, more costly to manufacture, and more difficult to protectagainst dust and contaminants. These systems are also less efficient inthe use of stored air pressure. They also have reduced pressurizedsurface areas on which the pressure to the piston can act, resulting ininefficient use of power and the need for a larger storage tank to holdthe compressed air (or other fluid), which is used to lift the vehicle.The tank required may reduce useable storage space, or even be so largethat it cannot fit into many vehicles in a practical manner, andtherefore is not able to be used in those vehicles.

It is a further object of the present invention to eliminate or reducethe effects of environmental contaminants and the damage they cause tolift system components. Lift system components are typically installednear the vehicle's suspension system's coil springs and the tires. Thelift system components are typically exposed to environmentalcontaminants such as dust, water, mud, sand or snow.

Prior art lift systems with cylinder and piston actuators that arepositioned around the coil springs, and that have exposed cylinderbores, are susceptible to damage caused by such environmentalcontaminants. While the damage to the cylinder bores and the piston-boreseals is an obvious problem, an effective solution for protecting thesecomponents from environmental contaminants has not been obvious.Developing a solution for protecting the cylinder bores fromenvironmental contaminants has been problematic because: 1) the cylinderbores are adjacent to a moving coil spring, and 2) because a piston mustbe able to slide within the cylinder bore without restriction, and 3)because the space for the cylinders is limited, and 4) the cylinders arefrequently located near a spinning tire that may move and turn as thevehicle is operated. These space constraints and moving elements imposemany design limitations that prevent the use of many conventionalsolutions that would otherwise be suitable to protect the cylinder bore.

For example rubber bellows would not be an effective solution forsealing around an active and long coil spring. Even if a rubber bellowswere to be used, it would be bulky and it would introduce anothercomponent that would be subject to wear and deterioration and it wouldintroduce additional problems.

Prior art vehicle lift systems with cylinder and piston actuators thatare positioned around the coil springs, such as those used by UmbrellaAuto Design, Roberuta, Phantom VIP, Fortune Auto Muller andStance-Solutions do not provide protection from environmentalcontaminants to their cylinder bores. They all use exposed andunprotected cylinder bores with the problems described above.

Prior art vehicle lift systems with cylinder and piston actuators thatpress against a coil spring are prone to misalignment of the pistonwithin the cylinder bore because the coil spring exerts uneven forcesupon the piston. The spring pressure against the lift system's piston isuneven for many reasons such as off-centered springs or movement of thesuspension system. In some cases, the springs could be mountedoff-centered relative to the piston, as shown in FIGS. 17 and 18. Theuneven spring pressure against the lift system's piston causes unevenforces upon the piston and this can result in the piston tilting ormoving off center (mis-alignment) within the cylinder bore.

In prior art, the tilting of the piston can result in the piston rubbingagainst the cylinder bore and causing damage to the cylinder bore and tothe piston-bore seal(s). In extreme cases, the piston can tilt enough tobecome seized within the cylinder bore.

In prior art lift systems, the pistons are made longer than wouldotherwise be necessary to reduce tilting or misalignment of the pistonwithin the cylinder bore. The pistons are cylindrical with piston-boreseals at the top of the piston and at the bottom of the piston. Thepistons are relatively long with seals at the top and the bottom of thepiston in an attempt to reduce the tilting or misalignment of the pistonand the resulting damage and malfunctions that could occur. In theseprior art lift systems, increasing the length (height) of the pistonhelps to reduce damage to the cylinder bore, however it reduces theeffective stroke or length of travel within a cylinder of a givenlength. These relatively long pistons usually require the use of shortercoil suspension springs to offset the added piston height. The use ofshorter coil springs reduces the suspension's travel and performance.

Prior art lift systems that use bump stops, typically do so in a mannerthat reduces the effective pressurized area above the bump stop, makingthe system less efficient and requiring more air pressure and/or storedpressurized air to operate properly. They also do not provide a meansfor having the bump stop travel in tandem with the piston withouttouching and causing any wear upon the shock absorber rod.

Some other prior art systems use hydraulic pumps and pressurized liquidto raise the vehicle, and use hollow, double-walled cylinders havingconcentric inner and outer walls. This type of system is less efficientand requires significantly higher operating pressures to be effective.Hydraulic systems also require more costly hydraulic pumps and/or tanksfilled with heavy hydraulic fluid and have the risk of fluid leaksand/or oil spills.

Hydraulic systems typically use cylinder and piston assemblies that arerelatively thick (tall) positioned on the top or bottom of the coilspring. They add considerable height to the spring and usually requirethe use of shorter coil springs. Using shorter coil springs normallyresults in a reduction of suspension travel and reduced suspensionperformance.

Hydraulic systems also pump fluid only when it is needed to lift avehicle. Thus, they are slower acting systems that require strong pumpsto raise a vehicle with enough speed to be effective. They draw higheramperage on a vehicle's electrical system. Further, because hydraulicsystems typically raise vehicles slowly, they are not practical to usein many driving situations.

Prior art lift systems also do not have an adjustable, automatedactivation system that automatically senses obstacles in a vehicle'spath and raises or lowers the vehicle based on the vehicle's proximityto the obstacles and its speed.

Other lift systems use components, such as large pneumatic cylinders orlarge air tanks that are often too large to install into many vehicles.These larger components also add undesirable weight to the vehicle, thusdecreasing vehicle performance and efficiency.

Other systems that use compressed air tanks may also allow condensation(water) in the air tank to be passed through the air outlet port undercertain driving conditions, which may cause surges of the water (surgewater). Examples of such conditions include acceleration, braking andcornering. The surge water that passes through the air lines to thevalves, pressure sensors, cylinders and other components has detrimentaleffects on these components.

Prior art lift systems include: Umbrella Auto Design, Roberuta, PhantomVIP, Fortune Auto Muller, Stance-Solutions, Top Secret, Mode Parfum,Skipper, KW Hydraulic Lift System, Tech-Art, Ram Lift Pro, AirForce,AirRex, Air Lift, and Accuair.

It is an object of the present invention to provide an affordable liftsystem that is adaptable to a large variety of vehicles.

It is another object of the present invention to provide an efficientlift system that only requires small pressurized cylinders and storagetanks and to provide increased piston travel (stroke) within a cylinderof a given length to provide increased lifting capabilities while usingshorter cylinders.

It is another object of the present invention to provide a lift systemthat adds only a small amount of height to the coil spring.

It is another object of the present invention to provide an effectivemeans to eliminate wear and damage to cylinder bores caused by contactof the pistons with the cylinder bores by eliminating contact of thepistons with the cylinder bores.

It is another object of the present invention to provide an effectivemeans to control the tilting of pistons in cylinder bores of liftsystems and to eliminate the problems associated with the tilting ofpistons in cylinder bores of a lift systems.

It is another object of the present invention to provide an effectivemeans to eliminate wear and damage to cylinder bores and to piston-boreseals caused by environmental contaminants.

It is a further object to provide means for operating the system in safemanner that does not require the driver to take his eyes off the road(to look for and operate switches), and to make the operation of thesystem automatic and hands-free.

It is a further object to provide an effective means to automaticallyadjust the height of a vehicle to provide adequate ground clearance totraverse over obstacles in the vehicle's path.

It is still a further object to overcome the drawbacks relating to theprior art devices discussed above and to provide at least some of thebenefits described below.

DISCLOSURE OF THE INVENTION

The above and other objects are achieved by a device for lifting avehicle that has a support or suspension system to support the weight ofthe vehicle. The support or suspension system preferably comprises acoil spring and shock absorber with a shock absorber shaft and a shockabsorber body. The coil spring may be coiled around the shock absorbershaft. Alternatively, a vehicle may not have a shock absorber or theshock absorber may be mounted separately and apart from the coil spring.In some vehicles the weight of the vehicle is not supported by asuspension system with coil springs. They may use leaf springs, discsprings, air springs or other mechanical, hydraulic, pneumatic,magnetic, electrical, electro-mechanical devices or solid mounts tosupport the weight of the vehicle. The present invention can be adaptedto accommodate a wide variety of vehicles with these and other types ofconventional or other suspension or weight support systems.

In the preferred embodiment shown in FIG. 1 the device furtherpreferably comprises a hollow cylinder having a cylinder inner diameter(cylinder bore) larger than the coil spring outer diameter. The cylinderis formed by a cylinder top with a cylinder top rim, and cylindricalcylinder side walls connected to, and extending downwardly from thecylinder top rim to a cylinder bottom. The cylinder top and saidcylinder side walls define an inner cylinder bore. An inlet port extendsinwardly from the cylinder top into the hollow cylinder. There is alsoan inner circumferential retaining ring groove located near the cylinderbottom. A retaining ring is also retained in the inner circumferentialretaining ring groove. The retaining ring creates a barrier between thepiston skirt (described below) and the cylinder side walls to preventcontaminants from entering said cylinder bore. The retaining ring alsoacts as a positive stop against the piston's lower circumferential rim(described below), thus limiting the travel of the piston.

The device also comprises a substantially cylindrical piston having apiston diameter less than the cylinder bore diameter, slidable withinthe cylinder bore. The piston has a circular piston top with a pistontop rim and a piston lower circumferential rim.

Preferably, a cylindrical coil spring flange extends downwardly from thepiston top. Preferably, a bump stop flange extends inwardly—from thecoil spring flange. Preferably, a bump stop having one or more bump stopgrooves is retained in the bump stop flange.

Preferably, there is also an outer circumferential piston-bore sealgroove parallel to, and downwardly spaced apart from, the top outercircumference of the piston. A piston-bore seal is also preferablyretained in the piston-bore seal groove. The piston-bore seal preferablycontains a wiper to clean the cylinder bore when the cylinder and thepiston slide apart.

Preferably, there is a piston lower circumferential rim 37 on thecircumference of said piston top. The piston lower circumferential rim37 has a diameter that is larger than the inner diameter of theretaining ring. This piston rim limits the travel of the piston bycontacting the retaining ring at the bottom of the cylinder.

Preferably, this device also contains a substantially cylindrical pistonskirt that extends downwardly from the piston lower circumferential rim.

The piston skirt diameter is undersized to be substantially smaller thanthe cylinder bore diameter and smaller than the inside diameter of theretaining ring. The undersized piston skirt preferably covers the fulllength of the cylinder bore to protect the cylinder bore fromcontaminants.

Preferably the piston diameter and the piston skirt outer diameter aresufficiently less than the cylinder bore diameter whereby the piston andthe piston skirt can tilt within the cylinder bore up to 5 degrees ormore when the piston is being installed into the cylinder.

Preferably, the piston skirt has a circular piston skirt bottom flangeattached to or integrally formed with the piston skirt bottom thatextends outwardly from the piston skirt. Preferably the bottom flange ispositioned immediately below the retaining ring when the piston ispositioned fully within the cylinder.

Preferably the piston skirt, the piston skirt bottom flange, theretaining ring and the cylinder inner diameter are sized and positionedto fit closely together to form a system of interlocking barriers toprevent environmental contaminants such as dust, sand, water, mud andsnow from reaching the cylinder bore. The undersized piston skirt, thepiston skirt bottom flange, the retaining ring and the cylinder innerdiameter eliminate virtually all of the damage to the bore caused byenvironmental contaminants.

Other prior art devices without this system of contaminant barriers suchas those used by Umbrella Auto Design, Roberuta, Top Secret, PhantomVIP, Fortune Auto Muller and Stance-Solutions have cylinder bores thatare exposed to the environmental contaminants and they suffer fromcontaminants that damage the cylinder bores and the piston-bore seals.

While such damage to the exposed cylinder bores and the piston-boreseals is obvious, the solution to the problem was not obvious becausethe cylinder bores surround moving coil springs that restrict themethods for sealing the cylinder bore from contaminants. The damage tosuch exposed cylinder bores and piston-bore seals can be so serious thatthose devices with unprotected, exposed cylinder bores are not suitablefor use by OEM automobile manufacturers.

The device illustrated in FIG. 1 virtually eliminates all of the damageand wear to the cylinder bores and to the piston-bore seals caused byenvironmental contaminants, making the device much more desirable to OEMautomobile manufacturers who desire trouble-free performance andmaintenance-free systems.

The retaining ring and the undersized piston skirt do not limit thestroke or travel of the piston. The undersized piston skirt travelsbeyond the bottom of the cylinder and passes through the retaining ringwhen the piston slides down within the cylinder bore.

In prior art illustrated in FIGS. 2 and 3, the coil springs may pressunevenly upon the piston's spring perch. The uneven force tends to tiltthe piston. In the present invention, the extended and undersized pistonskirt acts as an extended lever that is connected to the piston top toprevent the piston from tilting excessively once all of the componentshave been assembled. This extended and undersized piston skirt does notlimit the stroke of the piston.

The undersized piston skirt does not touch the cylinder bore when thepiston slides within the cylinder, thus the piston skirt causes no wearupon the cylinder bore. Preferably the outside diameter of the pistonskirt is sized to fit closely to the inside diameter of the retainingring whereby the retaining ring prevents the piston skirt and the pistontop from tilting excessively within the cylinder.

The piston diameter and the skirt diameter are preferably sufficientlyless than the cylinder bore diameter to allow the piston skirt to tiltor wobble within the cylinder bore during assembly and before theretaining ring, or an alternative cylinder ring, is installed near thebottom of the cylinder. The ability of the piston to tilt within thecylinder bore facilitates the assembly of the piston with a piston-boreseal into the cylinder.

The skirt is preferably tapered inwardly between the skirt top and theskirt bottom. The piston and the piston skirt can also preferably beintegrally formed instead of being separate components. The piston top,cylinder top, piston bore seal, and the cylinder side walls form anexpandable pressure space that is in fluid communication with the inletport.

The device is activated when a pressurized fluid enters through theinlet port into the expandable pressure space and causes the piston andcylinder to slide apart, thereby raising the vehicle. The device isdeactivated when the pressurized fluid exits through the inlet port fromthe expandable pressure space and causes the piston and cylinder toslide together, thereby lowering the vehicle. The pressurized fluid ispreferably pressurized air.

Preferably the piston-bore seal is sized to keep the piston top centeredwithin the cylinder bore, and the outside diameter of the piston issized sufficiently smaller than the cylinder bore diameter so that thepiston never touches the cylinder bore when the piston with thepiston-bore seal, the piston skirt and the retaining ring are installed.Preferably the piston-bore seal is the only part that touches thecylinder bore, and the cylinder bore and the seal experience very littlewear and a long working life resulting in lower maintenance and higherreliability than other devices wherein the piston can touch and damagethe cylinder bore.

The present invention also preferably contains an interface operablyconnected to the device that uses existing original equipmentmanufacturer switches such as cruise control switches to activate anddeactivate the device, and a control unit, preferably an electroniccontrol unit, operably connected to the device for automatic sensing ofthe vehicle's ground clearance and speed. The control unit can also bean optical or optoelectronic or other control unit that can perform thesame functions as an electronic control unit.

Preferably, the lift system is automatically activated if there is lessthan the desired ground clearance in the vehicle's path, such as ifthere is an obstacle (such as a speed bump) in the path. Preferably alsothe lift system is automatically deactivated if there is more than thedesired ground clearance in the vehicle's path, such as if the systemhas been activated, but the obstacle (such as a speed bump) is no longerin the vehicle's path.

Preferably also, activation of the lift system is automaticallyprevented if the vehicle is traveling at an excessive speed, such aswhere raising of the vehicle by the lift system would adversely affectthe handling of the vehicle, or where the speed would interfere with theoperating of the cruise control. Preferably also, the lift systemautomatically deactivates if the vehicle is traveling at an excessivespeed, to avoid adversely affecting handling of the vehicle, or wherethe speed would interfere with the operating of the cruise control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of the present invention'scylinder, piston and undersized piston skirt for adjusting the height ofa vehicle.

FIG. 2 is a cross-sectional view of a first prior art device, whichcontains a hollow double-walled cylinder with concentric inner and outercylinder walls and a ring-shaped piston.

FIG. 3 is a cross-sectional view of a second prior art device.

FIG. 4 is a cross-sectional view of an earlier version of the presentinvention (that is mounted on a shock absorber shaft) with the pistontilted in an off-axis orientation relative to the cylinder (wobblingwithin the cylinder) as it would be during assembly of the piston intothe cylinder or disassembly of the piston out of the cylinder.

FIG. 5 is a cross-sectional view of the present invention's seal betweenthe piston and cylinder bore (piston-bore seal).

FIG. 6 is a cross-sectional view of a simple prior art piston-bore seal.

FIG. 7 is a cross-sectional view of the earlier version of FIG. 4's sealbetween the cylinder and the shock absorber shaft (cylinder-shaft seal).

FIG. 8 is a cross-sectional view of the present invention's seal betweenthe piston and shock absorber shaft (piston-shaft seal).

FIG. 9 is a flow diagram of how the present invention operates throughthe use of an Electronic Control Unit (ECU), sensors and other controls.

FIG. 10 is a longitudinal cross-sectional view of an alternate presentlypreferred embodiment of the invention.

FIG. 11 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 12 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 13 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 14 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 15 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 16 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention.

FIG. 17 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention. In this embodiment thecoil spring C is located off-centered relative to the center of theother components.

FIG. 18 is a longitudinal cross-sectional view of another alternatepresently preferred embodiment of the invention. In this embodiment, theshock absorber shaft S, the cylinder shaft seal 28, the piston shaftseal 38 and the coil spring C are off-centered relative to the centersof the cylinder 22 and the piston 32.

DESCRIPTION OF A PRESENTLY PREFERRED EMBODIMENT

Referring to FIG. 1, shown is a longitudinal cross-sectional view of thepresently preferred embodiment of the invention comprising a liftingdevice that includes a coil spring C beneath a vehicle's chassis (orbody). The circular top 12 of the hollow cylinder rests against thevehicle's underbody (or chassis) to support the weight of the vehicle. Apiston 32 is positioned inside the cylinder 22 and is proportioned fortravel within the cylinder bore 18. The piston 32 is situated at the topof the coil spring C. The weight of the vehicle is supported by coilsprings C through the springs' contact with the pistons' spring perchsection 36. The cylinder 22, piston 32, and optional rubber or plasticbump stop 10, and optional dust shield (11) are preferably coaxial witheach other.

The cylinder 22 preferably has a substantially circular cylinder top 12.The cylinder has an inlet port 14 for the passage of pressurized fluidsor gasses into and out of the cylinder 22 for activation anddeactivation of the lift system. The cylinder 22 is hollow and has asingle wall, with an outer cylinder wall surface 16 and an innercylinder wall surface (or cylinder bore) 18.

The piston 32 rests inside the hollow cylinder 22 (when the lift systemis deactivated) and is proportioned for travel within the cylinder bore18. The piston 32 may be constructed of metal, plastic or any othersuitable materials. The piston has a piston outer circumferential rim 37on the circumference of said piston top. This piston rim 37 has adiameter that is larger than the inner diameter of a retaining ring 72in the inner circumferential retaining ring groove 20 located near thebottom of the cylinder bore 18. The piston rim 37 limits the stroke ofthe piston by contacting the retaining ring 72. The piston 32 has anundersized piston-skirt 62 that acts as an extended lever on the pistonand limits the pivoting of the piston when it is installed in thecylinder 22.

The top of the piston skirt 62 preferably contains a tapered section 56,which aids in the alignment of the piston 32 with the center of thecylinder 22 through the tapered section's contact with the retainingring 72 when the piston is fully extended (activated). Likewise, thebottom of the piston skirt 62 preferably has an outwardly taperedsection 58 that also aids in the alignment of the piston 32 with thecenter of the cylinder 22 when the piston is fully retracted(deactivated). These features assist in keeping the axis of the pistonin alignment with the axis of the cylinder when the piston is extendedor retracted, and they help to eliminate the need to bear against thecylinder bore 18 to facilitate alignment. The piston skirt 62 preferablyhas a circumference that is large enough keep the piston 32 in alignmentwith the cylinder 22 and small enough to allow the installation of theretaining ring 72 when the piston is being installed in the cylinder.Preferably, the diameter of the piston skirt (skirt diameter) 62 is nolarger than the cylinder bore 18, minus two times the width of theretaining ring's 72 radial wall thickness, minus the depth of theretaining ring groove 20 in the cylinder. The piston skirt 62 does notcome into contact with, or wear upon, the cylinder bore 18. The pistonskirt 62 only comes into contact with the retaining ring 72, which is adurable component and is not a sealing surface. By eliminating contactof the piston with the cylinder bore 18 (the inner wall of thecylinder), the wear upon the cylinder bore that would otherwise occurfrom contact with the piston 32 or the piston skirt 62 is completelyeliminated and the life of the cylinder's bore 18 and the piston-boreseal 40 are greatly improved.

The piston skirt 62 has an unconventionally large gap between the skirtand the cylinder bore 18. The large gap (illustrated in FIG. 4) allowsthe piston 32 and piston skirt 62 to be installed into the cylinder 22in a highly pivoted orientation, which in turn allows for the use ofseals with complex designs, such as highly compliant, over-sized sealinglips 41 and a wiper feature (wiper) 42, as illustrated in FIG. 5, in thepreferred device. These types of seals cannot be used in systems thatrestrict wobbling (tilting or canting) of the piston 32 during assemblybecause the wiper feature 42 and the sealing lip 41 would become lodgedin the retaining ring groove 20, if the piston 32 entered or exited thecylinder 22 with the seals parallel to the groove as is done in theprior art. Wipers 42 are desirable because they wipe contaminants fromthe surface of the cylinder bore 18 every time the piston 32 isactivated and travels downward in the cylinder 22, specifically thecylinder bore 18.

The piston skirt 62 may be integrally formed with the piston to form asingle piece, or it may be a separate modular component that can beattached to the piston 32 using conventional methods, such as a pressfit or friction fit. By using a separate modular attachable pistonskirt, different lengths of the piston skirt can adjust the total lengthof the piston 32 to accommodate various lengths of travel of the piston(or piston strokes) that may be desirable in conjunction with cylindersof various lengths.

In another preferred embodiment of the invention, the piston 32 has aremovable piston skirt 62 that allows the piston to be rotated 360degrees within the cylinder 22 during assembly. The skirt 62 may beattached to the piston after the piston has been inserted into thecylinder. This is not possible in the prior art devices shown in FIGS. 2and 3. By employing removable piston skirt(s) that allow extensiverotation of the piston within the cylinder during assembly, an evenwider range of seals and wipers may be used with the benefits that comewith those seals and wipers. Additionally, by employing the use ofremovable piston skirts, the overall length of the piston can easily bealtered to match the lengths of various cylinders, thus enabling thepiston to have effective strokes of various lengths that may bedesirable for various vehicles or various applications.

Returning to FIG. 1, preferably, the piston skirt 62 has a circularbottom flange 64 extending outwardly from the bottom of the piston skirt62. This circular bottom flange 64 and the piston skirt 62 work inconjunction with the retaining ring 72 to keep the piston in properalignment relative to the cylinder 22, while the piston 32 is extendingor retracting within the cylinder 22. These components along with thecylinder's bore 18 also serve as a system of interlocking components toshield the cylinder bore 18 from dust and other contaminants, to reducewear and improve the life of the cylinder bore 18, the piston-bore seal40, and the piston skirt 62. The circular bottom flange 64 also providesadded strength and rigidity to the piston skirt 62.

The piston 32 preferably has a coil spring flange 46 extendingdownwardly from the piston top to retain the coil spring C in the properposition relative to the bottom of the piston. This coil spring flange46 preferably also has a bump stop flange 48 extending inwardly towardthe shock absorber shaft to retain an elastomeric bump stop 10. Thispositioning of the bump stop enables it to move in tandem with thepiston 32 and the top of the coil spring C as the piston is activatedand deactivated.

In the presently preferred embodiment of the invention, the piston 32has a circumferential groove (piston-bore seal groove) 35 that retains apiston-bore seal 40 to form an airtight seal between the piston 32 andcylinder bore 18. The piston-bore seal 40 may be located at the samelevel as the spring perch 36, or at a level that is higher or lower thanthe spring perch 36. The spring perch 36 rests on the top of the coilspring C. Ideally, the spring perch 36 is located as high as possible tominimize the height of the piston 32 that is situated on the top of thecoil spring C.

The top rim of the piston preferably also has a reduced diameterrelative to the rest of the piston due to a preferred outercircumferential inlet recess 34 that circles the top of the piston. Thereduced dimension of the top rim of the piston provides severalsignificant benefits.

The circumferential inlet recess 34 allows a pressurized fluid to enterand exit the cylinder port 14 faster and it also allows the piston totravel within the cylinder 22 without interfering with any fittinginstalled into the inlet port 14 when the fitting extends inward beyondthe cylinder bore 18. This helps to minimize the added height to the topof the coil spring C compared to lift systems in the prior art and italso permits the use of a cylinder 22 with a smaller outer diameter tofit in vehicles with space limitations.

The presently preferred embodiment of the invention uses compressed air,however, other pressurized gases or fluids (mediums) may be used in thealternative.

The reduced dimension of the top of the piston increases the piston's 32ability to wobble (cant or tilt) within the cylinder 22 to facilitatethe installation and the removal of the piston 32 from the cylinder 22.See FIG. 4. Preferably, the piston 32 and the cylinder 22 are allowed towobble-up to 5 degrees or more.

FIG. 4 illustrates how the piston 32 of an earlier version of thepresent invention (that mounts on a shock absorber shaft) is able towobble (or cant or tilt) relative to the cylinder 22 during assembly ofthe piston into the cylinder, due in part to: the piston skirt 62 havinga diameter that is significantly smaller than the diameter of thecylinder bore and/or a removable undersized skirt, the cylinder notbeing double-walled, and the piston 32 having a reduced diameter at thetop. FIG. 4 demonstrates how the piston-bore seal 40 can pass over theretaining ring groove 20 without being parallel to the groove. Thisgreatly facilitates the use of seals 40 that have larger sizes and/orother features, such as over-sized sealing lips and/or wipers that wouldnot be able to easily pass over the retaining ring groove 20 in thecylinder in a parallel orientation. The ability of the piston to wobble(or cant or tilt) within the cylinder, and to use seals that performbetter, greatly improves the operation, durability, and reliability ofthe lifting apparatus in the present invention.

Without the ability for the piston 32 to wobble (or cant or tilt) withinthe cylinder, the piston-bore seal 40 would become lodged in theretaining ring groove 20 during installation or removal of the piston.The ability to tilt the piston 32 and piston-bore seal 40 out ofparallel alignment with the retaining ring groove 20 allows the piston32 and piston-bore seal 40 to pass over the retaining ring groove 20without becoming lodged or damaged. The ability to wobble or cant thepiston also allows for the use of piston-bore seals 40 with advantageousconfigurations and features, including over-sized upper sealing lips 41and wiper features 42 (both shown in FIG. 5) that provide better sealingcapabilities, clean the cylinder bore every time the piston is activated(when the piston 32 and cylinder 22 slide apart), greatly reduces thewear on the cylinder's bore, and increases the life of the cylinder andthe bore seals. The wobbling (tilting or canting) allows for the use ofsuch seals because without the wobbling, the seals would otherwisebecome lodged in the retaining ring groove 20 resulting in damage to theseals.

Referring to FIG. 1, the piston-bore seal 40 works in conjunction withthe smooth surface of the cylinder bore 18 to form an airtight andexpandable pressure space between the cylinder and the top of thepiston. The retaining ring 72, inserted in the retaining ring groove 20,retains the piston 32 within the cylinder 22 by contacting the pistonlower circumferential rim 37 and works in conjunction with the pistonskirt 62 and upper 56 and lower 58 tapered sections of the piston skirtto maintain the alignment of the same relative to the vertical axis ofthe cylinder 22. The retaining ring 72 also serves as a barrier to keepdust and other contaminants away from the cylinder bore when the pistonis in its retracted (deactivated) position.

The presently preferred embodiment (as described above) providessignificant benefits over the prior art. Referring to FIG. 2, shown is aprior art device that uses a conventional cylinder 12 with an outercylinder bore (wall) 18, an inner cylinder bore (wall) 24 facing thepiston 32, and an inner cylinder bore (wall) 22 facing the shockabsorber shaft S. The inner cylinder bore (wall) 22 facing the shockabsorber shaft S has a larger diameter than the shock absorber shaft S.The diameter of the inner cylinder bore 24 facing the piston 32 must belarge enough to accommodate the thickness of the cylinder wall and anybump stop 10 and/or the shock absorber body B, as well as othercomponent, such as a possible dust sleeve, which may interfere with theoperation of the suspension system. During compression of the coilspring C, the shock absorber body B may move into the space within theinner cylinder bore (wall) 22 and thus the diameter of the innercylinder bore (wall) 22 must be large enough to accommodate the size ofthe shock absorber body B.

Within the outer cylinder bore 18 and the inner cylinder bore 24 thereis a ring shaped piston 32. This piston has inner seal(s) 39 that forman air tight seal against the inner wall 24 and outer seal(s) 40 thatform an airtight seal against the outer cylinder bore 18.

Pressurized fluid or gas is introduced through the inlet port 14 toactivate and press down upon the ring shaped piston 32. The annular areaon the top of the piston 32 between the inner cylinder wall 24 and theouter cylinder wall 18 is the effective pressurized area. It is only inthis area that pressure can be applied to the top of the piston, whichthen presses on the coil springs, to raise the cylinder 12 against theunderbody of the vehicle. The effective pressurized area issubstantially smaller than the effective pressurized area in thepresently preferred embodiment of the invention (as shown in FIG. 1),which results in a lower lifting capacity for the prior art device incomparison to the present invention.

For example, in order to lift a 1,000 pound load on a single liftingdevice, the prior art requires a storage tank that has 8.247 times thecapacity as the storage tank in the present invention. This assumes thecontrolled variables of a shock absorber with a 0.5″ shaft, a cylinderbore with a 4.5 inch inside diameter (ID), piston stroke of 2 inches,tank air pressure at 120 PSI and a lift load of 1,000 pounds on a singlecylinder.

Example of the Present Invention Vs Prior Art

The present invention utilizes the 0.5″ shock absorber shaft as itssealing surface (inner bore) while the prior art uses a 3″ inner bore.It is able to lift 1,000 pounds with a tank size of approximately 0.154Gallons. The prior art requires a tank size of 1.27 Gallons which is824.7% of the present invention required tank size.

The present invention requires a tank size of 0.154 gallons to lift1,000 pounds.

4.5″ ID of cylinder

0.5″ Shock Absorber Shaft diameter (serves as the inner bore)

120 PSI Tank Pressure

1,000 pounds Lift for a single cylinder

Tank Size Required: 0.154 Gallons

Prior art system requires a tank size of 1.270 gallons to lift 1,000pounds.

4.5″ ID of cylinder

3″ Inner bore of a conventional hollow cylinder example

120 PSI Tank Pressure

1,000 pounds Lift for a single cylinder

Tank Size Required: 1.270 Gallons

The present invention can lift 1,702 pounds with a 1.270 gallon tanksize.

4.5″ ID

0.5″ Shock Absorber Shaft diameter (serves as the inner bore)

120 PSI Tank Pressure

1,702 pounds Lift for a single cylinder

Tank Size: 1.27 Gallons

FIGS. 2 and 3 illustrate the inner piston seals 39 and the outer pistonseals 40 in the prior art devices. Due to limited available space forthe seals and the coil spring C, the location, size, and design of theseals are restricted. To avoid interference between the seals and thecoil spring C, the seals may be positioned above the coil spring asshown in FIGS. 2 and 3. As a result, the piston 32 must be thicker toaccommodate the seals, and the top of the coil spring must be relocatedto a lower position than in the present invention. This means that theground clearance of the vehicle will not be as low as it could be. Tooffset this raising of the vehicle, the original coil spring C may needto be replaced with a shorter coil spring at an added cost and withreduced performance.

The pistons 32 used in prior art, as shown in FIGS. 2 and 3, are alsorestricted from wobbling (or canting) within the cylinder 12 to preventthe seals 39, 40 from losing contact with the cylinder bore 18 (in FIG.2), and the outer cylinder bore (wall) 18 and an inner cylinder bore(wall) 24 facing the piston 32 (in FIG. 3), which would result in a leakand failure of the lift system. Thus, the pistons 32 are designed to bethick (and tall) enough to prevent excessive wobbling (or canting)within the cylinder. The walls of the cylinder are used to guide thepiston and keep it in alignment with the cylinder. The pistons are alsodesigned to fit more snugly into the cylinders than in the presentinvention. This also prevents the pistons from wobbling excessively.This arrangement makes it difficult or impossible to use seals that maybecome lodged in any grooves in the cylinder wall such the groove 20 forthe retaining ring.

The pistons used in prior art also have outer circumference cylindricalsurfaces that extend substantially in the longitudinal or axialdirection, as illustrated in FIGS. 2 and 3. The length of the outercylindrical surface must be long enough to maintain the axial alignmentof the piston in the cylinder bore. In the present invention,illustrated in FIG. 1, the piston 32 uses an undersized piston skirt 62that is much smaller in diameter than the piston top, much smaller thanthe piston lower circumferential rim 37 and much smaller than thecylinder bore 18 to help maintain axial alignment of the piston 32relative to the cylinder bore 18. The top sealing section of the piston32 is above the skirt 62 and it is shorter in the axial direction thanthe cylindrical outer surface of pistons used in prior art.

In the prior art, shown in FIGS. 2 and 3, the piston 32 cannot travellower than the retaining ring 72, which limits the extension and strokeof the piston. In contrast, the piston skirt 62 in the presentlypreferred embodiment of the invention, shown in FIG. 1, can easilytravel lower than the retaining ring 72. This means the piston has alonger effective stroke than the prior art devices. This longer strokeresults in the ability to lift vehicles to a greater height than inprior art with a cylinder of the same axial length. Whereas a prior artcylinder would need to be longer to accommodate the thickness of thepiston. Most cars, however, have space limitations that restrict theuseable size of a suspension lifting device. The present invention usesa device that maximizes the stroke length of the piston within a givencylinder height so that the device can be effectively used in vehicleswith space limitations.

Referring back to FIG. 1, the top of the coil spring C may extend higherthan the piston-bore seal 40 without interfering with that piston-boreseal 40. This feature significantly reduces the thickness of the pistonthat rests on top of the coil spring C and therefore allows the vehicleto be at a lower ground clearance when the system is not active. Thisreduced thickness of the piston top eliminates or significantly reducesthe need to replace the original coil spring C with a shorter coilspring to maintain proper normal vehicle height. It also significantlyreduces the overall length, weight, and cost of the present invention'scylinder and piston assembly while providing added stroke length for thepiston compared to the prior art shown in FIGS. 2 and 3.

The practical range for the thickness of the piston top in the presentlypreferred embodiment is approximately between 3 to 25 mm. Preferably,the thickness should be approximately in the range of 3 and 10 mm.Optimally, the thickness should be approximately in the range of 3 to 6mm.

The prior art as shown in FIGS. 2 and 3 do not provide protection fromcontamination of the outer cylinder bore (wall) 18, the inner cylinderwall 24, the shock absorber shaft S, or the shock absorber shaft seal.There is no practical way to protect all of these surfaces withoutlosing efficiency and/or lifting capability of the prior art systemshown in FIG. 2. The lack of protection from contaminants results inadded wear, shorter useful life of the components, lower reliability andhigher maintenance costs than in my invention shown in FIG. 1.

Referring to FIG. 2, it is difficult or impossible to use a dust sleeveto protect the shock absorber shafts from contaminants without reducingthe effective pressurized area to press upon the piston. The innercylinder wall 22 occupies the space that would be needed by a dustsleeve unless the inner cylinder wall 22 was moved further away from theshock absorber shaft S. In order to accommodate the use of a bump stopand a dust sleeve that is large enough to fit over the shock absorberbody B, the prior art's hollow cylinder inner wall surface 22 would needto be large enough to accommodate a dust sleeve within the insidediameter of the cylinder wall. This would greatly reduce the effectivepressurized area over the ring shaped piston 32 and may render thepiston 32 incapable of generating enough lifting force to raise thevehicle.

The piston-bore seal 40 used in the present invention, shown in FIG. 1may be made of rubber, urethane or other commonly used seal materials.FIG. 5 illustrates a cross-sectional view of a presently preferredembodiment of a piston-bore seal 40. FIG. 7 illustrates cross-sectionalview of a prior version of the invention (mounted on a shock absorbershaft) having a cylinder-shaft seal 28. FIG. 8 illustrates across-sectional view of the prior version having a piston-shaft seal 38.

The piston-bore seal 40 in FIG. 5 has an upper sealing lip 41 with anover-sized dimension relative to the cylinder bore. This seal has bettersealing capabilities than a simple seal, as illustrated in FIG. 6,especially if the piston is allowed to wobble (cant or tilt) within thecylinder. A seal with an over-sized upper sealing lip 41 would becomelodged in the retaining ring groove if it were inserted into a cylinderwithout tilting the piston and seal at an angle to the groove. The wiper42 section of the seal in FIG. 5 serves to wipe contaminants from thecylinder bore when the piston is activated to move downward to raise thevehicle. This reduces the amount of contaminants on the cylinder borethat would otherwise contact the upper sealing lip 41. By wipingcontaminants from the cylinder bore, the wiper 42 reduces wear on thebore and seal and prolongs the useful life of these components.

FIG. 6 illustrates a simple seal 44 that is typically used in the priorart devices shown in FIGS. 2 and 3. This type of seal is used because itcan traverse over a groove in the cylinder, such as the retaining ringgroove 20, without becoming lodged in the groove. However, this type ofseal also has a number of shortcomings. As shown in FIG. 3, the simpleseal would not seal well if the piston 32 were to wobble (cant) inrelation to the cylinder bore 18. If the piston 32 were to wobble, thesimple seal would lose contact with the cylinder's bore 18 and the sealwould fail to maintain pressure. To prevent this failure, prior artsystems restrict the wobbling of the pistons in the cylinder. This isaccomplished in various ways, such as the use of double cylinder wallsas illustrated in FIG. 2. The prior art also uses thick (tall or long)cylindrical piston designs that cannot wobble within the cylinderbecause of a close tolerance fit to the cylinder bore as shown in FIG.3.

Another problem with simple seals 44 used in prior art (as illustratedin FIG. 6) is that they allow more contaminants to pass over the seal'ssealing surface resulting in abrasion and damage to the seals and thecylinder bore. This type of seal does not have the ability toeffectively wipe debris or contaminants from the cylinder bore 18 asdoes the seal with the wiper feature 42 illustrated in FIG. 5.

In the prior art, as shown in FIG. 2, the piston 32 is retained inalignment with the cylinder 12 by an outer cylinder bore (wall) 18 andan inner cylinder bore (wall) 24 facing the piston 32. This arrangementdoes not allow the piston to wobble (cant or tilt) once it is installedin the cylinder. This means that the piston seals 39, 40 remain parallelwith any features in the cylinder walls 18, 24, such as the retainingring groove 20, during assembly and dis-assembly of piston with thecylinder. Because the seals 39, 40 will enter and exit the cylinder in aposition that is parallel with the retaining ring groove 20, they wouldtend to become lodged in the groove if they are large enough to do so.This can result in damage to the seals and it prohibits the use of sealswith beneficial features, such as larger sealing lips with greatercompression and/or compliance with the cylinder bore and better sealingcapabilities. An example of a seal with beneficial design features isthe use of wiper feature 42, as illustrated in FIG. 5, to clean thebore(s) and reduce wear of the inner and outer cylinder walls 18, 24 asillustrated in FIG. 2 and the seals 39, 40. Wiper seals would have wiperblades to wipe contaminants from the cylinder walls (bores).

FIG. 10 illustrates another presently preferred embodiment of theinvention. In this embodiment, cylinder 22 has an upper retaining ringgroove 21 and a lower retaining ring groove 20 located at the bottom ofthe cylinder bore 18. An upper retaining ring 70 is located in the upperretaining ring groove 21. A lower retaining ring 72 is located in thelower retaining ring groove 20. A guide ring 71 is located between theupper retaining ring 70 and the lower retaining ring 72. The guide ring71 extends inwardly, farther than either the upper retaining ring 70 orlower retaining ring 72, so that it comes into contact the undersizedpiston skirt 62 instead of the upper and lower retaining rings 70 and72. The guide ring 71 is preferably made of Teflon or any other suitablesmooth material.

The use of a smooth surfaced (Teflon) guide ring 71 is preferablebecause it is used to guide the piston skirt 62 instead of the hard(metal) retaining rings 70, 72. This reduces wear on the piston skirt62, thus prolonging the life of the piston skirt 62 and reducing repairand/or replacement costs.

FIG. 11 illustrates another presently preferred embodiment of theinvention. The piston 32 has a circumferential piston rim 37 at the topof the piston 32 to serve as a positive stop that limits the travel ofthe piston 32 in the cylinder 22. The piston 32 has an undersized pistonskirt 62 that is smooth and straight (not tapered). The piston skirt 62is undersized relative to the cylinder bore 18 sufficiently to preventthe piston skirt from touching the cylinder bore. The pistoncircumferential rim 37 has a larger diameter than the undersized pistonskirt 62. The piston skirt 62 is attached to the piston top and extendsdownward preferably to the bottom of the cylinder. The piston skirt 62is guided by the piston seal 78. The piston skirt is attached to the topof the piston 32 below the piston circumferential rim 37, and the pistonskirt serves as an extended lever attached to the piston to preventexcessive tilting of the piston. The piston circumferential rim 37prevents the piston from tilting excessively in the cylinder bore 18.The piston circumferential rim 37 also prevents the undersized pistonskirt 62 from touching the cylinder bore 18, thus protecting the pistonskirt 62 from wear and damage from any contact with the cylinder bore.The piston skirt 62 also protects the cylinder bore from environmentalcontaminants such as dust, mud, water, sand and snow. The piston skirt62 does not limit the travel of the piston within the cylinder bore 18because it is sized substantially smaller than the cylinder bore and itcan travel beyond the bottom of the cylinder.

A cylinder ring 74 is attached to the bottom of the cylinder side wallsthrough conventional methods, such as screw threads 75 in the cylinderring 74 and the bottom of the cylinder 12. The cylinder ring 74 has acylinder retaining ring flange 76 that extends inward to limit thetravel of the piston 32, by engaging lower surface of the pistoncircumferential rim 37. The cylinder ring 74 has a cylinder ring groove77 to retain a cylinder ring seal 78. The cylinder ring seal 78preferably forms an air-tight seal between the cylinder ring 74 and thepiston skirt 62. The bottom edge of the piston skirt (at the skirtbottom) preferably has a taper 79 to facilitate the assembly of thecylinder ring seal 78 over the bottom edge of the piston 79.

FIG. 12 illustrates a variant of the preferred embodiment shown inFIG. 1. In this variant, the device is used with a coil spring without ashock absorber. The cylinder 22 and the piston 32 both have solid topswithout apertures or seals, whereas the preferred embodiment illustratedin FIG. 1 shows apertures and seals in the centers of the cylinder 22and the piston 32. Furthermore this variant of the preferred embodimentillustrated in FIG. 12 does not have a dust shield 11 as shown in theembodiment illustrated in FIG. 1.

FIG. 13 illustrates a variant of the preferred embodiment shown in FIG.10. In this variant, the device is used with a coil spring without ashock absorber. The cylinder 22 and the piston 32 both have solid topswhereas the preferred embodiment illustrated in FIG. 10 shows aperturesand seals in the centers of the cylinder 22 and the piston 32.Furthermore this variant of the preferred embodiment illustrated in FIG.13 does not have a dust shield 11 as shown in the embodiment illustratedin FIG. 10.

FIG. 14 illustrates a variant of the preferred embodiment shown in FIG.11. In this variant, the device is used with a coil spring without ashock absorber. The cylinder 22 and the piston 32 both have solid topswhereas the preferred embodiment illustrated in FIG. 11 shows aperturesand seals in the centers of the cylinder 22 and the piston 32.Furthermore this variant of the preferred embodiment illustrated in FIG.14 does not have a dust shield 11 as shown in the embodiment illustratedin FIG. 11.

FIGS. 15 and 16 illustrate variants of the preferred embodiment shown inFIGS. 1 and 12. In FIGS. 15 and 16, the top of the piston 32 is shownwith a diameter that is smaller than the cylinder bore 18, but not assmall as the variant shown in FIG. 1. The outer top rim of the pistonsin FIGS. 15 and 16 are larger in comparison to the reduced diameter ofthe piston lower circumferential rim 34 illustrated in FIG. 1. Thereforethe embodiments shown in FIGS. 15 and 16 do not provide the benefits ofimproved air flow into the device and they do not provide additionalclearance for any fitting that might be installed into the inlet port14. The piston 32 in FIG. 15 illustrates an embodiment with a shockabsorber shaft S and FIG. 16 illustrates an embodiment without a shockabsorber shaft.

Referring to FIGS. 1, 10, 12, 13, 15, 16, 17 and 18, a piston 32 ispositioned inside the cylinder 22 and is proportioned for travel withinthe cylinder bore 18. The piston 32 is situated at the top of the coilspring C. The piston 32 has a piston lower circumferential rim 37 on thepiston's circumference under a piston-bore seal 40.

For installations where the device is mounted at the top of a coilspring and a shock absorber as illustrated in FIGS. 1, 10, 15, 17 and18, the device preferably has apertures in the tops of the cylinder 22and the piston 32 with a cylinder seal 28 and a piston seal 38 mountedin said apertures, for sealing against a shock absorber shaft S.Alternatively, for use in installations with a coil spring C but with noshock absorber, or where the shock absorber is mounted separately andaway from the coil spring as illustrated in FIGS. 12, 13 and 16, thecylinder 22 and the piston 32 can have solid tops with no apertures andno seals.

In FIGS. 1, 10, 12, 13, 15, 16, 17 and 18, a circumferential retainingring groove 20 is located at the bottom of the bore 18 and a retainingring 72 is retained in the retaining ring groove. The retaining ring 72limits the stroke of the piston 32 by stopping the stroke of the pistonwhen the piston lower circumferential rim 37 contacts the retaining ring72.

An undersized piston skirt 62 is attached to the piston top below thepiston lower circumferential rim 37. The outer diameter of the pistonskirt 62 is smaller than the inner diameter of the retaining ring 72.The outer diameter of the piston skirt 62 is substantially smaller thanthe diameter of the cylinder bore 18.

The retaining ring 72 also serves as an alignment ring that keeps thepiston 32 and the piston skirt 62 in alignment with the axis of the bore18 of the cylinder 22 and does not allow excessive tilting of the piston32 and the piston skirt 62 within the bore 18. The use of the undersizedpiston skirt 62 and a retaining ring 72 as an alignment system allowsthe use of a very short piston top that would not function as wellwithout the undersized piston skirt 62. If a piston top with a shortlength did not use the undersized piston skirt 62 to keep it inalignment with the axis of the bore, the piston top could tilt out ofalignment with the axis of the bore 18 and the piston 32 could scrapeagainst the bore 18 causing damage to the bore. The piston 32 could alsobecome seized in the bore 18 unless the piston were long enough toprevent tilting and/or seizing. Also, the piston-bore seal could leak ifthe piston were allowed to tilt excessively.

It is desirable to have a short piston top because the length of thepiston top limits the piston stroke within the cylinder and also limitsthe resulting lift that the piston can provide for the vehicle.Furthermore, short piston tops can accommodate longer suspension springsthan a tall piston top. This is important because the shorter pistontops allow for a wider range of spring lengths for increased suspensiontravel and better suspension performance.

The undersized diameter of the piston skirt 62 allows the piston skirtto travel within the cylinder's bore 18 without touching the bore. Theundersized piston skirt 62 does not cause any wear on the cylinder bore18 because it is undersized sufficiently to not touch the bore 18. Theundersized piston skirt 62 protects the bore of the cylinder from damagethat could happen when a piston tilts excessively, making contact withand causes wear and damage to the bore 18.

The undersized piston skirt 62 does not limit the travel of the pistonbecause it is sufficiently smaller than the retaining ring 72 to allowthe piston skirt 62 to travel out past the retaining ring 72 and beyondthe bottom of the cylinder. The retaining ring 72 does not retain thepiston skirt 62 within the cylinder 22, but it does retain the pistonlower circumferential rim 37 and the piston 32 inside the cylinder.

The piston skirt 62 protects the cylinder bore 18 from dirt andcontaminants that would accumulate in the bore if the piston did nothave the undersized piston skirt 62 and the bore were left exposed. Thepiston skirt preferably has a bottom flange 64 extending outwardly belowthe retaining ring 72. The piston skirt 62, the retaining ring 72, thepiston skirt's bottom flange 64 and the cylinder bore 18 act together asa system of interlocking barriers to prevent contaminants such as dirt,mud, water, sand and snow from collecting onto the cylinder bore 18,thus eliminating the damage and wear that would otherwise occur to thebore 18 and the piston-bore seal 35 when the piston 32 slides within thecylinder bore 18.

The weight of the vehicle is transferred through the cylinder 22 to thepiston 32 then to the coil spring C. The coil spring C may press againstthe piston spring perch 36 unevenly due to the spring's movement and thegeometry and movement of the vehicle's suspension components. When thespring presses against the piston's spring perch 36 unevenly, the forcestend to tilt the piston out of alignment with the cylinder's bore 18.Excessive tilting of the piston 32 could result in the piston seal 40leaking and/or the piston making contact with and scraping the cylinderbore 18. The piston skirt 62 located at the bottom of the piston 32provides a lever arm to maintain the alignment of the piston 32 and thepiston seal 40 at the top of the piston. Thus, the undersized pistonskirt 62 prevents excessive tilting of the piston 32 without the need touse tall pistons and multiple seals, as used in prior art andillustrated in FIGS. 2 and 3.

FIG. 11 illustrates an alternative preferred embodiment for a device foradjusting the height of a vehicle that utilizes an undersized pistonskirt 62 that does not come into contact with the cylinder bore 18.Preventing contact between the cylinder bore 18 and the piston skirt 62results in less wear upon the cylinder bore 18 and the piston skirt 62resulting in longer life of these parts and less cost for repairs. Thepiston 32 has a circumferential rim 37 that is sized to slide within thecylinder bore 18 and to engage a retaining ring 76 located at the bottomof the cylinder 16. During assembly, the piston 32 can tilt within thecylinder bore 18 until the cylinder ring 74 and the cylinder ring seal78 are installed onto the cylinder 16. Once the cylinder ring 74 andcylinder ring seal 78 are installed, they form an air-tight seal withthe undersized piston skirt 62 and maintain adequate alignment of thepiston 32 within the cylinder 12.

The undersized piston skirt 62 is sized sufficiently smaller than thepiston circumferential rim 37 so that the piston skirt can slide throughthe inside diameter of the retaining ring 76. The undersized pistonskirt 62 is sufficiently smaller than the cylinder bore 18 to not touchor cause any wear or damage upon the cylinder bore.

The spring C presses against the piston's spring perch 36. This forcefrom the spring may be uneven and it could excessively tilt the pistonin prior art devices illustrated in FIGS. 2 and 3. Uneven pressure fromthe coil spring C on the bottom of the piston 32 in prior art devicescan cause the piston to tilt excessively and scrape the cylinder bore18, causing damage to the bore and to the seals 40. The deviceillustrated in FIG. 11 solves this problem by having the seal 78 at thebottom of the cylinder 16 and a circumferential piston rim 37 at the topof the piston and an undersized piston skirt 62 that maintainssufficient alignment of the piston 32 in the cylinder 22. As unevenforce presses against the piston's spring perch 36, the piston's outercircumferential rim 37 at the piston top, located at the opposite end ofthe piston skirt from the seal 78, the piston skirt 62 and the pistonseal 78 prevent the piston from tilting excessively.

In this device, the undersized piston skirt 62 is the sealing surfacethat seals against the piston seal 78. The piston skirt is sizedproportionately to allow it to slide within the cylinder bore withouttouching the cylinder bore or any other component except the seal 78. Byavoiding contact with any component other than the piston seal 78, theundersized piston skirt 62 in this embodiment does not experience anywear from contact with such components.

The undersized piston skirt 62, the cylinder 16, the cylinder ring 76and the seal 78 form a system of barriers to protect the device fromenvironmental contaminants such as dust, water, mud, sand and snow.

The cylinder ring 74 may be made in various lengths to provide a meansof easily altering the length of the cylinder 12 and cylinder ring 74assembly. Likewise, the cylinder 12 may be made in various lengths toalter the length of the cylinder 12 and cylinder ring 74 assembly. Byaltering the length of the cylinder 12 and the cylinder ring 74assembly, the stroke of the piston 32 within the cylinder 12 can alteredto achieve various stroke lengths.

The cylinder ring 74 may be made in any length and may effectivelyreplace the cylinder side walls. Likewise, the cylinder 12 may be madein any length and may be so short that the cylinder side walls areeffectively replaced by the cylinder ring 74 with adequate length toprovide adequate stroke length for the piston 32.

FIG. 14 illustrates a variant of the preferred embodiment shown in FIG.11. In this variant, the device is used with a coil spring without ashock absorber. The cylinder 22 and the piston 32 both have solid topswhereas the preferred embodiment illustrated in FIG. 11 has aperturesand seals in the centers of the cylinder 22 and the piston 32.Furthermore this variant of the preferred embodiment illustrated in FIG.14 does not have a dust shield 11 as shown in the embodiment illustratedin FIG. 11.

Activation of the Lifting System, Manual Buttons, Cruise Control Buttonsand Automated Activation

Referring to FIG. 1, in the presently preferred embodiment of theinvention, the piston 32 is activated by the introduction of apressurized fluid, such as compressed air, through the inlet port 14.The pressurized air activates the device by pushing the piston 32downward and the cylinder 12 upward (the piston and cylinder slideapart). The force of the cylinder being pushed upward raises the vehiclewhen the force is great enough to overcome the weight of the vehicle.When the device is deactivated, the pressurized fluid (preferably air)rushes out of the inlet port 14 and the piston 32 and cylinder 12 returnto their resting position adjacent to each other (the piston andcylinder slide together).

FIG. 9 shows a flow diagram of the lift system. First a compressor pump82 generates compressed air that is stored in a storage tank 80. Thecompressed air is released from the storage tank 80 into the cylinderand piston assemblies 88 and 89 preferably for two or four wheelsthrough the opening of one or more up valve(s) 84 to raise the vehicle,at preferably either two wheels or four wheels. To lower the vehicleback to its normal state, a down valve 86 is opened to release the airfrom the cylinder and piston assemblies.

The up valve(s) 84 and the down valve(s) 86 may be activated by variousmeans such as manual switches or controls. In a presently preferredembodiment, a Control Unit, preferably an Electronic Control Unit (ECU)90 is employed. The ECU receives inputs from various sources such asproximity sensor(s) 102 and a speed sensor 104 and from push button(s)92 and cruise control buttons 94, 96 and 98, which are preferablycontrolled by an operator or a driver. The proximity sensor preferablyis a ground clearance sensor that senses, monitors or calculates groundclearance. Ground clearance sensor is defined as a device with the meansto measure ground clearance, calculate present or future groundclearance, estimate ground clearance or provide a signal or data whichcan be used in whole or in part to calculate or estimate present orfuture ground clearance. Ground clearance sensors may include proximitysensors, ultrasonic sensors, infrared sensors, capacitive dischargesensors and photo optic devices. The push button(s) 92, and cruisecontrol buttons 94, 96 and 98 may be the Original Equipment Manufacturer(OEM) cruise control buttons and/or they may be any combination of anyOEM button(s) or after-market button(s). The push buttons may also berocker switches, or push button type switches or any other type ofswitch. They may have LED or other lights that display one or morecolors to indicate status or for basic illumination. The lights may belit constantly or pulsed at various frequencies to indicate the statusof various functions and/or settings, or to provide feedback to the userwhen setting parameters to the control system. Additional feedback isoptionally provided to the driver through audible devices, such asbuzzers or speakers, which can be varied in their tone and/or volume toindicate such things as the status of the operation of the system orconfirmation of commands to the system.

The invention may be installed on the front wheels only or on the frontand rear wheels of vehicles. The front and rear devices may be activatedsimultaneously, or independently from each other. They may also beactivated with a delay between the front and rear devices.

Many vehicles have existing switches or OEM cruise control systems withpress buttons that are located on or near the steering wheel to safelyactivate a vehicle's cruise control system. These buttons can be safelyactivated without the need for a driver to take his eyes off the road tolook for the buttons because they are easily accessible at or near adriver's fingertips. These OEM cruise control systems typically do notoperate at slower vehicle speeds because cruise control systems areintended to be used at highway speeds. Thus, these systems are perfectfor a dual use in connection with the present invention, which is onlyactivated when a vehicle is at a slower speed as it approaches anobstacle in its path.

In the presently preferred embodiment of the invention, the ECU 90 hasan interface that responds to outputs from the OEM cruise controlbuttons 94, 96 and 98 when the OEM cruise control system is not in use.The OEM cruise control buttons are used to perform various functions.For example, the cruise control Main switch 94 can be used to turn thevehicle's cruise control functions on or off and to activate ordeactivate the lift system. When the OEM cruise control system is turnedoff or is inactive, such as when the vehicle is travelling too slowlyfor the OEM cruise control system to function, and the lift system isturned on, the output from the Accel button 96 can be used, for example,to activate the lifting of the lift system and the vehicle. The ECU 90can be programmed to respond to presses to the OEM cruise controlbuttons 96 and 98 whereby the ECU 90 will raise or lower the lift systemwhen the OEM cruise control system is turned off or when the OEM cruisecontrol system is inactive due to inadequate speed for the OEM cruisecontrol system to function. The Decel button 98 can be used to initiatethe lowering of the lift system. Alternatively, other existing switchesmay be used to control the lift system.

Prior art vehicle lift systems require the operator to take his eyes offthe road so that a driver can look for and press an after-market manualswitch that is added to the vehicle for raising and lowering of thevehicle. The use of the OEM cruise control system interface in thepresent invention provides a convenient and safer method for activatingthe lift system. It also eliminates the need for after-market switch(es)to be installed in the vehicle, which would require additional labor andcosts.

The OEM cruise control system interface also enables the cruise controlbuttons to be used to select and activate other features, for exampleproximity sensors and speed sensors. The sensors or devices can beinstalled on or under the vehicle in one or more locations. Theproximity sensors or devices are preferably adjusted or calibrated toactivate the ECU and the lift system at the desired distances fromobstacles. When a signal from the proximity sensor(s) to the ECUindicates that the sensor is closer to an obstacle than desired, the ECUactivates the up valve(s) 84 to raise the vehicle away from theobstacle. The ECU uses various parameters, such as time and proximity,to check for the presence of obstacles, and automatically lowers thevehicle to the normal state when the desired conditions are met. The ECUmay also receive input signals from a vehicle speed sensor. The ECU mayuse such information to control or limit the raising and/or lowering ofthe vehicle depending on the speed of the vehicle.

The ECU 90 may be programmed in a variety of ways. For example, the ECU90 can be programmed directly through the use of the push button(s) 92and cruise control buttons 94, 96 and 98. It can also be configuredthrough the use of a computer connected to the ECU and/or through theuse of DIP switches, portable flash drives or other devices. The ECU 90may also be programmed to modify its response to inputs (adjustment)regarding time durations for the activation of the up valve and downvalve; delay time for the starting of the compressor pump upon startingthe vehicle; duration for the vehicle to remain in the lifted positionprior to activating the lowering of the vehicle; proximity distancesettings for the automatic activation of the lifting and lowering of thevehicle; sensitivity and speed settings for the input signals from theproximity sensor(s); vehicle speed settings for various functions suchas for limiting the lifting of the vehicle and for the automatedlowering of the vehicle if excessive vehicle speed is detected. Thesetypes of parameters may be programmed into the ECU 90 and/or the usermay select or adjust the parameters affecting the ECU 90 and itsoperation of the invention.

While the present invention has been disclosed in connection with thepresently preferred embodiments described herein, it should beunderstood that there may be other embodiments which fall within thisspirit and scope of the invention as defined by the claims. Accordingly,no limitations are to be implied or inferred in this invention except asspecifically and as explicitly set forth in the claims.

INDUSTRIAL APPLICABILITY

This invention can be used whenever it is necessary to lift a vehicle toavoid a collision with an obstacle in the vehicle's path or for otherreasons.

I claim:
 1. A vehicle having a ground clearance and a suspension systemthat can controllably lift and lower the vehicle to achieve a desiredground clearance, wherein the improvement comprises: a control unit forcontrolling the suspension system, operably connected to the suspensionsystem; a ground clearance sensor for sensing the ground clearance inthe vehicle's path, operably connected to the control unit; wherein thecontrol unit automatically lifts the vehicle when the ground clearancesensor senses the ground clearance in the vehicle's path to be less thanthe desired ground clearance; wherein the control unit automaticallylowers the vehicle when the around clearance sensor senses the groundclearance in the vehicle's path to be greater than the desired groundclearance; a vehicle speed sensor to sense excessive speed of thevehicle, operably connected to the control unit; wherein the controlunit prevents activation of the suspension system and lifting of thevehicle if the speed sensor senses excessive speed while the vehicle isin a lowered position; and wherein the control unit deactivates liftingof the vehicle by the suspension system and lowers the vehicle if thespeed sensor senses excessive speed while the vehicle is in a raisedposition.
 2. A vehicle having a ground clearance and a suspension systemthat can controllably lift and lower the vehicle to achieve a desiredground clearance, operably connected to a control unit, wherein theimprovement comprises: a ground clearance sensor for sensing the groundclearance in the vehicle's path, operably connected to the control unit;wherein the control unit automatically activates the suspension systemto lift the vehicle when the ground clearance sensor senses the groundclearance in the vehicle's path to be less than the desired groundclearance; wherein the control unit automatically deactivates thesuspension system to lower the vehicle when the ground clearance sensorsenses the ground clearance in the vehicle's path to be greater than thedesired ground clearance; and a vehicle speed sensor to sense excessivespeed of the vehicle, operably connected to the control unit; whereinthe control unit prevents activation of the suspension system andlifting of the vehicle if the speed sensor senses excessive speed whilethe vehicle is in a lowered position; and wherein the control unitdeactivates lifting of the vehicle by the suspension system and lowersthe vehicle if the speed sensor senses excessive speed while the vehicleis in a raised position.
 3. A process for automatically adjusting groundclearance of a vehicle having a suspension system that can controllablylift and lower the vehicle to achieve a desired ground clearance,operably connected to a control unit, comprising: providing a groundclearance sensor operably connected to the control unit: wherein, inresponse to the ground clearance sensor sensing a ground clearance inthe vehicle's path to be less than the desired ground clearance, thecontrol unit causes the suspension system to automatically lift thevehicle; and wherein, in response to the ground clearance sensor sensinga ground clearance in the vehicle's path to be more than the desiredground clearance, the control unit causes the suspension system toautomatically lower the vehicle; providing a vehicle speed sensoroperably connected to the control unit; wherein, in response to thevehicle speed sensor sensing excessive speed of the vehicle while in alowered position, the control unit causes the suspension system toprevent activation of the suspension system and lifting of the vehicle;and wherein, in response to the vehicle speed sensor sensing excessivespeed of the vehicle while in a raised position, the control unit causesthe suspension system to automatically deactivate lifting of the vehicleby the suspension system and lowers the vehicle.